Lake Tanganyika cichlids — species, locations & maps

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Spathodus sp. 'erythrodon white zaire' Mtoto.jpg

Petrochromis sp. 'gold' Mtoto<br><font color=gray>Petrochromis cf. horii 'Yellow' Mtoto</font>

Tribe / Genus:	Tropheini / Petrochromis
Biotope:	They inhabit rocky habitat and most likely also intermediate habitat. They are found only at greater depths. Territorial males occur at depths greater than 20 m, where they defend their territory only weakly. Females are also found at slightly shallower depths (between 10 and 15 m) and do not hold territories.
Geographic distribution:	Petrochromis sp. 'gold' occurs in the south western and west central part, between Cape Kachese (Zambia) and Cape Tembwe (DR Congo). According to some authors P. sp. ‘Gold’ is synonym of P. horii, but according to African Diving, pending a taxonomic analysis of the group and especially of the three undescribed species, is better to regard this one as possible distinct species.
Typical adult size:	They grow to a size between 15 and 20 cm. Males of this size are no longer bright yellow, but become greyish with vertical bars. Females are noticeably smaller than males.
Sexual dimorphism:	Females are noticeably smaller than males. As males increase in size, they also undergo a pronounced color change from bright yellow to a greyer coloration with vertical barring.
Recommended aquarium size:	An aquarium of at least 500 liters is recommended.
Aquarium setup:	The aquarium should contain as many rocks as possible, arranged to create separate, distinct areas with larger rock piles. Despite the rock masses, there should still be plenty of open swimming space between them. A sand substrate should be used on the bottom.
Diet:	Herbivorous. Petrochromis are known for an exceptional appetite. In the wild they mainly feed on algae scraped from rocks. In the aquarium they should be provided primarily with foods high in spirulina (flakes, pellets, etc.).
Breeding:	Typical mouthbrooders. The male lures the female into his territory, where the female begins to lay eggs, which she immediately picks up into her mouth. Once all eggs are in her mouth, she tries to pick up the egg dummies on the male’s anal fin, at which point the male releases sperm, which the female takes into her mouth. Fertilization therefore takes place inside the female’s mouth. Fry numbers are not high, usually only around 15 in the wild and around 30 in the aquarium. After about 30 days the female releases the fry, which are already fairly large and capable of surviving on their own. It is notable that the female continues to feed normally throughout the brooding period, which is unusual for most other mouthbrooders.
Aggression:	Petrochromis are extremely aggressive cichlids primarily within their own species (males and females). They are therefore best kept in larger groups so that aggression is spread out. Toward other species in the aquarium they generally show less direct aggression, but males defend their territories. Unlike most other Petrochromis, members of the “Petrochromis horii species group” are considerably less aggressive, which is likely related to their deeper-water lifestyle, having been pushed into deeper zones by more aggressive Petrochromis living in shallower water.
Special notes:	Petrochromis sp. 'gold' belongs to the so-called Petrochromis horii species group, referred to by Ad Konings as “Petrochromis of the deep”. According to African Diving Ltd, this group comprises four distinct species. Because these Petrochromis inhabit depths greater than 20 m (with territorial males occurring even deeper), all members of the group remain poorly studied. Members of the P. horii species group are distributed throughout the southern part of Lake Tanganyika, occurring along the central Tanzanian coast in Mahale National Park, continuing along the entire southern Tanzanian shoreline, through Zambia, and further along the southern Congolese coast as far as Cape Tembwe (according to African Diving Ltd). Exact distribution boundaries between the individual species of the group are largely unresolved due to their deep-water habitat and the resulting lack of comprehensive observations. The group currently includes the following forms: Petrochromis horii – the only formally described species of the group, yet arguably the least known. Apart from photographs by Adrian Indermaur from Kapwensolo and Kalambo Lodge, very few images exist beyond those used for the original description. The species was described from specimens collected at Kasenga, Zambia, where the largest individual was a female measuring about 14 cm. Takahashi & Koblmüller (2014) therefore suggested the possibility of females being larger than males, a hypothesis P. Tawil considers highly unlikely, maintaining that males are probably substantially larger, although this remains undocumented. Apart from the mentioned Zambian localities in the extreme south-eastern part of the lake, no confirmed records from other areas exist. Petrochromis sp. ‘gold’ – included within P. horii by Ad Konings in Tanganyika Cichlids in their Natural Habitat (4th edition), although he notes that further research may show it to represent a distinct species. According to Konings (2019), it occurs from Katete in Zambia to Mtoto in the Democratic Republic of the Congo, while African Diving Ltd report its presence as far as Cape Tembwe. The name refers to the bright yellow coloration seen in subadult individuals; adult males are instead grey with vertical barring. Petrochromis sp. ‘red’ – found in the area between Lyamembe and the Lubulungu River. With the exception of Lyamembe, which lies just outside Mahale National Park at the southern edge of the range, the entire distribution is located within Mahale NP. In the aquarium hobby, this species is often incorrectly referred to as Petrochromis sp. 'Red’ Bulu Point', although it does not occur at Bulu Point. The use of this locality name is likely related to fishing restrictions within Mahale Mountains NP, with Bulu Point being just north of the protected area. The species is also sometimes mislabeled as originating from Sibwesa, but no suitable habitat exists there and the species does not occur at that location. Petrochromis sp. ‘red mpimbwe’ – the name used by African Diving Ltd; referred to by Ad Konings as P. sp. ‘kipili brown’, and by P. Tawil simply as P. sp. ‘brown’, all three names referring to the same form. This taxon is reported from Cape Mpimbwe southwards to Kambwimba, slightly north of the Kalambo River. Specimens from the Kambwimba and Kasanga areas are commonly known in the aquarium hobby as “Petrochromis Flametail”. African Diving Ltd and Ad Konings consider “Flametail” conspecific with P. sp. ‘red mpimbwe’ (= P. sp. ‘kipili brown’), whereas P. Tawil suggests Flametail may be closer to P. horii. This discussion is detailed by P. Tawil in “The deep-water Petrochromis” (Tanganyika Magazyn, issue 20). All four members of this group share a deep-water lifestyle and one particularly rare trait among Tropheini: the absence of false egg spots on the anal fin.